15 When Judah saw her, he thought her to be an harlot; because she had covered her face. 16 And he turned unto her by the way, and said, Go to, I pray thee, let me come in unto thee; (for he knew not that she was his daughter in law.) And she said, What wilt thou give me, that thou mayest come in unto me? 17 And he said, I will send thee a kid from the flock. And she said, Wilt thou give me a pledge, till thou send it? 18 And he said, What pledge shall I give thee? And she said, Thy signet, and thy bracelets, and thy staff that is in thine hand. And he gave it her, and came in unto her, and she conceived by him.
The family soap opera takes a shocking turn as Tamar seduces her own father-in-law under the pretense of being a prostitute. As mentioned before, Judah had tried to pawn her off on her family, not leaving her many honorable recourses if she wanted to bear children, but this is still a highly unpleasant solution to her problem.
Fortunately for Tamar she thinks ahead, and tricks Judah into giving her all the personal signifiers that he is carrying. In other words, she takes his identity from him. And so it is with us whenever we give into temptation also. We do not only perform the act, we sell a part of ourselves to it. By her guile Tamar gained a position of power over Judah by obtaining direct evidence of his own shame. So, too, when we give a part of ourselves to sin, it gains power to drive us where we would not.